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Hmm, I hadn't thought of it that way. The way I was thinking of it was like this.When 1 is at TDC compression, 2 is at TDC exhaust.At the same time, 3 is at BDC intake. and 4 is at BDC after firing.

Turning the pass cam 180 would cause it to run as the 2 cyl. But, now you have me doubting that. I can't visualize the camshaft lobes in my head very well. Next time I'm in the garage I have an engine with the timing covers off that needs a rebuild or something. Still has compression on all cyls though, so maybe I'll mess around with that and see if it's even possible to get the compression at the same time on opposing cylinders.

i think you'll end up with intake valves opening at BDC instead of TDC at least on that one side.

it isn't clear from the OP what was intended so, yeah, maybe you could make it work that way too. I just went to the first arrangement that seemed like adjusting a cam would let a couple of cylinders be at compression at the same time. But, now, it seems either way requires custom cam(s).

Lets fix that...
The way the crank works, you wanna fire 1&2 at the same time, 3&4 at the same time, with a big pause in between fires for the engine to exhaust/intake. Gonna sound like a big lawn mower. (as if Sube engines didn't already)

This can easily be done with the stock wasted spark coil pack.

Cams are the basically the same, IIRC, except for the snout on the passenger cam sticks out of the end of the head, so you can just flip the drivers side cam to make it open/close valves together rather than in the normal sequence. Turn it 180. 360 degrees, (thats 1 whole turn) just puts it right back where it was in the first place. Prollem is, I think you'd end up with BANG BANG nothing nothing, when what you need is BANG nothing BANG nothing. Custom cams are gonna be a definite yes. Talk to Delta? Need someone who has the know how to either modify the existing cams, or design a custom set.

Ignition timing is done by the crank, injector timing is driven off the drivers cam sprocket. Some creative placement of weld beads on the back of the sprocket could possibly be used to trick the ECU into spraying when you need it to. I think this could be set up with a decent EM system. Just set it up to run a 2 cylinder engine, but use the "spray 2 injectors at the same time" idea.

Why hasn't anyone tried spinning the passenger's cam 180 deg and replacing the belt to see what happens? I'm 99% sure that the EJ subarus are still a batch fire setup so the EFI system should be able to do it, the knock sensor might have a hissy fit though.

I don't think custom cams are going to change much, you're going to end up with 1&2 firing then 3&4 firing one after the other, then the exhausting, sucking, squeezing without any power.

I can see how the V8s can get away with it, they're essentially running as a 4 cylinder with 4 bang events that can be spread out enough to match the 4th event in the cycle evenly to the 1st for a continuous spread for power strokes.

You'd probably have to look into a custom crank that would have all 4 pistons hitting TDC at the same time to achieve the double explosions at opposite ends of the cycle to make it a regular beat - there'd be one explosion per revolution, instead of the current 2 explosions per revolution.

If I've got this very wrong, flame away, I'm happy to stand corrected, but this is how my mind is thinking at the moment. It'd be a bit of fun to see what would happen, but a lot of work just for some ************s and giggles.

well, if you ditched the fuel injection for a carb, and had the cams made, it should work fine. the fact that it's wasted spark makes it all possible. efi would be either expensive or you depending on the impedance of the the ej injectors, you would have to splice 1 and 2 to fire together. (same with 3 and 4)

if they are high impedance injectors (usually 10-14 ohms) you can easily do this. splicing means two injectors have to run off one injector driver in the ecu. two lower impedance injectors that equal out the normal impedance wouldnt fry the driver, or not operate properly, with too much impedance. either that or you drop $1k on a REAL standalone ecu, not MS.

carburetion is the easy way out, and the cheap way. considering the fact that all big bang motors ive ever seen were in racing, where longevity isn't a concern, i wouldnt spend much on this without a pile of ej parts in my shed.